In the communications industry, as data transmission rates have steadily increased, crosstalk due to capacitive and inductive couplings among the closely spaced parallel conductors within the jack and/or plug has become increasingly problematic. Modular connectors with improved crosstalk performance have been designed to meet the increasingly demanding standards. Many of these improved connectors have included concepts disclosed in U.S. Pat. No. 5,997,358, the entirety of which is incorporated by reference herein. In particular, recent connectors have introduced predetermined amounts of crosstalk compensation to cancel offending near end crosstalk (NEXT). In some connectors, stages of compensation are used to account for phase shifts from propagation delay resulting from the distance between the compensation zone and the plug/jack interface. As a result, the magnitude and phase of the offending crosstalk is preferably offset by the compensation, which, in aggregate, has an equal magnitude, but opposite phase from the offending crosstalk.
Recent transmission rates, including those in excess of 500 MHz, have exceeded the capabilities of the techniques of existing jacks. Thus, jacks having improved compensation characteristics are needed.
There is a phase shift from an installed plug to the compensation zones in a jack which is dependent on the distance from the plug/jack electrical interface to the printed circuit board (PCB) which contains the compensation elements, and the dielectric of the surrounding materials. This phase shift is proportional to frequency and the magnitude of required compensation is dependent on the magnitude of phase shift. It is therefore advantageous to minimize this distance and phase shift to maximize the frequency range over which sufficient compensation is attained.
It is therefore advantageous to minimize the length of that portion of the jack contacts which electrically connects an installed plug to the PCB. However, a simple short cantilever contact is not mechanically sound.
An additional problem encountered in the design of electrical communication jacks is the fact that different types of plugs may be inserted into a jack—intentionally or unintentionally. For example, it is possible for a six-contact plug to be inserted into an eight-contact jack. In such a scenario, the six-contact plug will generally have a housing that will cause the first and eighth contacts—the outermost contacts—of the jack to flex farther than they would if an eight-contact plug were inserted into the jack. This can cause the outermost contacts of an eight-contact jack to take a permanent set, reducing or eliminating those contacts' ability to make proper contact with the first and eighth contacts of eight-contact plugs when they are later inserted. It is desirable to have a communication jack in which all contacts, including the outermost contacts, will not take a permanent set if a connector with six contacts is inserted into the jack.